Fishes of the Taquari-Antas river basin (Patos Lagoon basin), southern Brazil

Abstract

The aquatic habitats of the Taquari-Antas river basin (in the Patos Lagoon basin, southern Brazil) are under marked environmental transformation because of river damming for hydropower production. In order to provide an information baseline on the fish fauna of the Taquari-Antas basin, we provide a comprehensive survey of fish species based on primary and secondary data. We found 5,299 valid records of fish species in the basin, representing 119 species and 519 sampling sites. There are 13 non-native species, six of which are native to other Neotropical river basins. About 24% of the total native species are still lacking a taxonomic description at the species level. Three native long-distance migratory species were recorded (Leporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis), as well as two potential mid-distance migrators (Parapimelodus nigribarbis and Pimelodus pintado). Although there is only one officially endangered species in the basin (S. brasiliensis), restricted range species (21.7% of total species) should be considered in conservation efforts.Keywords: ichthyofauna, biodiversity, survey, neotropical, Rio Grande do Sul. Peixes da bacia do rio Taquari-Antas (sistema da Laguna dos Patos), sul do Brasil ResumoOs ambientes aquáticos da Bacia do rio Taquari-Antas (Bacia da Laguna dos Patos, sul do Brasil) vêm sofrendo considerável transformação, principalmente em razão da implantação de barragens para geração de energia elétrica. Com o objetivo de estabelecer um diagnóstico amplo da ictiofauna da Bacia do Taquari-Antas, realizou-se um inventário das espécies dessa bacia a partir de dados primários e secundários. Foram obtidos 5.299 registros válidos de espécies de peixe na bacia, representando 119 espécies e 519 localidades amostradas. Ocorrem, na bacia, 13 espécies não nativas, seis das quais são oriundas de outras bacias neotropicais. Cerca de 24% de todas as espécies carecem de descrição taxonômica no nível específico. Foram registradas três espécies nativas migradoras de longa distância (Leporinus obtusidens, Prochilodus lineatus e Salminus brasiliensis) e duas potenciais migradoras de média distância (Parapimelodus nigribarbis e Pimelodus pintado). O fato de uma espécie ser oficialmente reconhecida como ameaçada na bacia (S. brasiliensis) e a grande proporção de espécies de distribuição restrita (21,7% do total) devem ser levados em consideração nos esforços de conservação.Palavras-chave: ictiofauna, biodiversidade, inventário, neotropical, Rio Grande do Sul.

A new species of Astyanax Baird & Girard (Ostariophysi: Characidae) from the rio Taquari-Antas basin, southern Brazil

“…Among the Astyanax species that occur in the rio Taquari-Antas basin (Becker et al, 2013), A. henseli and A. laticeps are the ones with similar counts of maxillary teeth to that of A. bagual, but only the latter species possesses bony hooks on rays of all fins of males (vs. bony hooks present only on pelvic-and anal-fin rays). Furthermore, A.bagual can be distinguished from A. laticeps by the presence of two vertically elongate humeral spots (vs. one horizontally elongate spot), and by the number of branched anal-fin rays (24-28 vs. 15-23), and from A. henseli by the shape of the first humeral spot (see diagnosis), by the caudal peduncle spot (spot wide and expanded dorsally and ventrally vs. spot restricted to center of caudal peduncle; see Melo & Buckup, 2006), and an absence of space between the dentary teeth, which are slender vs. presence of space between dentary teeth.…”

“…The upper rio Taquari-Antas basin is recognized as an area of endemism for hosting a large number of endemic taxa (Carvalho & Reis, 2011;Becker et al, 2013;Ferrer & Malabarba, 2013;Lucena et al, 2013aLucena et al, , 2013b. According to Becker et al (2013), species with restricted ranges are potentially more susceptible to environmental impacts and extinction, and they should be considered as targets for assessments in conservation planning and environmental licensing. This is extremely relevant in the upper sections of the Taquari-Antas and Uruguay river basins due to the increasing number of dams implemented for hydroelectric power production and land transformation for forestry and agriculture.…”

Aspects of fish conservation in the upper Patos Lagoon basin

“…There are at least 16 non‐native species recorded in natural habitats of the Patos Lagoon basin (Table ; Becker et al ., , ; Leal et al ., ; Troca, ); about half of these species being from other South American river basins. In several newspaper articles published in the 1960s, there are records of the systematic releases of exotic fish species (unnamed) sponsored by the RS State government, including ‘silversides’, ‘trout’, ‘salmon’, ‘blackbass’ and ‘tilapia’.…”

“…() and Becker et al . () reported 12 and 13 invasive or exotic species in the Sinos River and in the Taquarí‐Antas River basins, two important tributaries of the Patos basin. Fish culture and stocking (including sport fishing) are the main causes of introductions, but inter‐basin connection caused by modification of landscape for water management and agriculture is also important.…”

A new species of Ituglanis (Siluriformes: Trichomycteridae) from the rio Uruguai basin, southern Brazil

“…Among the freshwater ecoregions of the southern Brazil sensu Abell et al (2008) -which includes the upper and lower rio Uruguai basin, Tramandaí-Mampituba, and Laguna dos Patos -the genus Ituglanis was first recorded by Becker et al (2013) only in the latter drainage. Since then, two species were described from the region: I. australis Datovo & de Pinna from the lower rio Uruguai and Laguna dos Patos, and I. boitata Ferrer, Donin & Malabarba from Tramandaí-Mampituba (Datovo, de Pinna, 2014;Ferrer et al, 2015).…”